What is the $SI$ unit of rate of diffusion for a gas?

Which gas volume is measured in a sample by using a solution of $CuCl$ in $NH_4OH$ through the measurement of volume change?

When an equal weight mixture of $SO_2$ and $O_2$ is taken in an empty container,the ratio of the partial pressure of $O_2$ to the total pressure is ......

In a container,the mole ratio of two gases $A$ and $B$ is $2 : 5$. The total pressure of the container is $3.5 \times 10^5 \ Pa$. If all molecules of $A$ are removed from the container,what will be the pressure exerted by the molecules of $B$?

The rate of diffusion of a gas is directly proportional to which of the following?

$CO_2$ and $N_2$ do not support combustion. However,$CO_2$ is preferred over $N_2$ for extinguishing fires because $CO_2$ .......